1. Field of the Invention
The invention relates to a novel disc tray loading mechanism. More particularly, the invention relates to a loading mechanism of a disc tray onto which recording medium discs such as compact discs, laser discs, or the like are set and which moves between a pull-out position at which the disc tray is pulled out of an outer casing and a pull-in position at which the disc tray is pulled into the outer casing.
2. Description of the Prior Art
There is a disc player using a known disc tray loading mechanism known as a linear skating type in which a tray on which a recording medium disc is set is pulled into the casing of the player substantially in a horizontal direction.
In a disc player of the type mentioned above, since a chucking of the recording medium disc is executed after completion of the loading of the disc tray, it is necessary to raise the disc tray or to lower the mechanical deck.
The tray loading mechanism of such a linear skating type executes the pull-in of the disc tray into the casing and the lowering operation of the disc tray or the raising operation of the mechanical deck by a single driving source.
Therefore, a tooth portion and a notched tooth portion are formed on a loading gear which comes into engagement with the rack formed on the disc tray. When the tooth portion is in engagement with the rack of the disc tray, the disc tray is moved in the horizontal direction. When the engagement between the rack of the disc tray and the loading gear is released by the notched tooth portion, the disc tray is descends or the mechanical deck is ascends.
FIGS. 1 and 2 show main sections of a disc tray loading mechanism a of the linear skating type in which the chucking of a recording medium disc is executed by raising a mechanical deck for the disc tray.
b denotes a thin box-shaped disc tray whose lower surface is open to the outside. A planar circular flat disc setting concave portion c is formed on the rear side of the disc tray b. The disc tray b is movable between a pull-in position at which the disc tray is supported by a guide portion of a casing (not shown) and is pulled into the casing and a pull-out position at which almost all of the disc tray is pulled out of the casing.
d indicates a rack which is integratedly formed on the lower surface of the disc tray b so as to extend in the moving direction and which is formed with a tooth portion on the left side surface. The rack d come into engagement with a loading gear, which will be explained hereinafter, and pulls out and in the disc tray b by a rotation of the, loading gear.
e denotes abutting members (only one is shown) which are formed on each side of the disc tray b side and restrict the pull-in position of the disc tray b. The abutting members e are vertically formed on the lower surface on this side of the disc tray b. A position where the abutting members e abut against a stopper member, which will be explained hereinafter, is set to the pull-in position.
f represents an abutted member on the disc tray b side for holding the disc tray b at the pull-in position. The abutted member f is vertically formed on the lower surface of the disc tray b and in the portion located above a loading gear, which will be explained hereinafter, at the pull-in position of the disc tray.
g denotes a loading gear which is rotatably supported on this side in the bottom plate of the casing and is rotated by a driving source (not shown). The loading gear has a flat gear shape and has a tooth portion h in which gear teeth are formed over almost 210.degree. of the peripheral edge of the loading gear and a remaining notched tooth portion i in which no gear teeth are formed.
j denotes a cam cylinder formed on the lower surface of the loading gear h and concentrically arranged therewith. A cam groove k is formed on the peripheral surface of the cam cylinder j.
l denotes a pull-in state holding member formed on the upper surface of the loading gear g. The holding member l is formed concentrically with the loading gear g so as to have an arc shape whose center span angle is set to about 165.degree. when it is seen as flat plane. On the other hand, a clockwise side edge of the pull-in state holding member l when it is seen from above and a counterclockwise side edge of the tooth portion h are separated from each other by an angle of about 110.degree. as a center angle.
On the other hand, for the cam groove k, the portion located below the tooth portion h of the loading gear g is formed in the upper portion of the cam cylinder j almost horizontally and the portion locating below the notched tooth portion i of the loading gear g is formed so as to be deviated to the lower side as it approaches the clockwise side.
m denotes a stopper member which is projected at a position close to this side of the bottom plate of the casing. When the disc tray b comes to the pull-in position, the abutting member e abuts against the stopper member m, thereby blocking the disc tray b from being further pulled in.
n denotes a mechanical deck arranged behind the loading gear g in the casing. A turn table o is rotatably supported on the rear edge portion of the mechanical deck n and a pickup p is supported on the front side of the turn table o so as to be movable in the front/rear direction. On the other hand, an engaging member q is formed in the front edge potion of the mechanical deck n.
The mechanical deck n is rotatably supported to a supporting shaft r which is fixed to the casing in a manner such that the front position of the portion to which the pickup p is supported extends in the right/left direction. Both of the front and rear edges of the mechanical deck n vertically swing like a seesaw. The engaging member q is slidably engaged with the cam groove k of the cam cylinder j of the loading gear g. When the engaging position of the cam groove k is low, the mechanical deck n is set into an almost horizontal state. The turn table o and the pickup p are located so as to be slightly projected to the upper position from the bottom surface of the disc setting concave portion c of the disc tray b. On the other hand, when the engaging position with the cam groove k is high, the mechanical deck n is obliquely positioned so that the rear edge is set at a lower position.
When the mechanical deck n is moved into the horizontal state and the turn table o and the pickup p are slightly projected from the bottom surface of the disc setting concave portion c, a disc s placed on the disc setting concave portion c is chucked by the turn table o. On the other hand, when the mechanical deck n is inclined, the chucking of the disc s is cancelled disengaged and the disc s is again set onto the disc setting concave portion c, so that the disc tray b can be pulled out from the casing.
The disc tray loading mechanism a as mentioned above operates in the following manner.
First, in a state in which the disc tray b is located at the pull-out position, the teeth of the rack d close to the rear edge are in engagement with the teeth of the tooth portion h of the loading gear g which are located on the counterclockwise side edge. The loading gear g rotates counterclockwise from this state, thereby moving the rack d rearwardly and pulling the disc tray b into the casing. In this state, the engaging member q of the mechanical deck n is in engagement with the upper cam groove k of the cam cylinder j, so that the mechanical deck n is held in the inclined state.
Then, the disc tray b is pulled into the casing and abutting member e abuts against the stopper member m on the casing side and, at the same time, the engagement between the tooth of the tooth portion h of the loading gear g which is located at the clockwise side edge and the tooth of the rack d which is located at the front edge is cancelled. The pull-in state holding member l of the loading gear g comes from the left side when it is seen from the front direction. The inner peripheral surface of the pull-in state holding member comes into engagement with the front edge surface of the abutted member f of the disc tray b. Thus, even if the loading gear g further rotates counterclockwise, the disc tray b does not move rearwardly. On the other hand, the disc tray b is not pulled out forwardly due to the engagement between the pull-in state holding member l and the abutted member f and is held at the pull-in position.
When the loading gear g further rotates counterclockwise from the above state, the engaging member q is guided by the cam groove k and is deviated downwardly. The mechanical deck n is set into the horizontal state and the turn table o chucks the discs, thereby obtaining a state in which the recording or reproduction can be performed.
However, in such a disc tray loading mechanism a, there are problems such that when the disc tray b reaches the pull-in position, the abutting member e abuts on the stopper member m on the casing side and a collision sound is generated and that a shock due to the collision is fairly propagated to the mechanical deck n or the circuit board or the like and an adverse influence is exerted on the disc player having an optical system.